Changing food may require some adaptation of the stomach, to get used to the new food.
Your cat may also need to get used to the new taste, smell, texture or kibble size/shape.
If changes are done gradually, though, it will usually be a smooth and successful process. A gradual switch, mixing more and more of the new food into the old one, should be done over a period of 7-10 days. This is important for any change of diet.
The exception is in cases of acute illness where a specialised diet must be introduced as quickly as possible, e.g. a digestive support or intensive care diet.
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